Perhaps you should try some spelling variations:
sang tao » hang tai
hanh vai » hanh vi, hanh va, hanh tai
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
duc van » duc va, duc tan, duc manh
vuc van » luc van, thuc van, chuc van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
tao hoi » tao khoi, tao boi, tay hoi
ky sang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky sang tao hoi. ((hieu ve) or (hieu va)) cam ((vuc van) OR (duc van)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang tao hoi. ((hieu ve) OR (hieu va)) cam ((vuc van) OR (duc van)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang tao hoi. ((hieu ve) or (hieu va)) cam ((vuc van) OR (duc van)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang tao hoi. ((hieu ve) or (hieu va)) cam ((vuc van) OR (duc van)) hanh vai cua tre*.